vertical arrays

Archived from groups: rec.audio.tech (More info?)

I have been looking at various speaker designs and wondered why more people
don't build or produce vertical arrays. Is it the cost involved or the size
or ??? They certainly seem to have a number of good characteristics. Am I
missing something?

r


--
Nothing beats the bandwidth of a station wagon filled with DLT tapes.

Archived from groups: rec.audio.tech (More info?)

Rich Andrews. wrote:
> I have been looking at various speaker designs and wondered why more people
> don't build or produce vertical arrays. Is it the cost involved or the size
> or ??? They certainly seem to have a number of good characteristics. Am I
> missing something?

The church I go to recently looked into getting a vertical line array
system, but it rapidly became apparent that our auditorium was too small
for such a speaker system. In order to be in the far field, the
audience should not be closer that 25 to 30 metres from the line array.
Our audience is only 15m away. Also, you need a fairly large
vertical height in which to hang the array, again, our building could
not accomodate such a system.

As great as they are, unless your building is acousically large, it does
not make much sense to use a line array. Alternatively, line arrays are
excellent for outdoor events.

Here in the UK, I went to a "son et lumiere" style evening at Audley End
House last summer, where there was a symphony orchestra and fireworks.
There must have been 15,000 people there that evening and on either side
of the stage was a line array column. The sound from quality was
fantastic, with very little SPL variation over the entire audience depth
(about 500m).

Take a look at http://www.l-acoustics.com/pdfproda/wavefront.zip for
more details on the theory behind line arrays.

Chris W

--
The voice of ignorance speaks loud and long,
but the words of the wise are quiet and few.
--

Archived from groups: rec.audio.tech (More info?)

Chris Whealy <chris.whealy.NO@SPAMsap.com> wrote in news:c5j0o9$7bs$1@news1.wdf.sap-ag.de:

> Rich Andrews. wrote:
>> I have been looking at various speaker designs and wondered why more people
>> don't build or produce vertical arrays. Is it the cost involved or the size
>> or ??? They certainly seem to have a number of good characteristics. Am I
>> missing something?
>
> The church I go to recently looked into getting a vertical line array
> system, but it rapidly became apparent that our auditorium was too small
> for such a speaker system. In order to be in the far field, the
> audience should not be closer that 25 to 30 metres from the line array.
> Our audience is only 15m away. Also, you need a fairly large
> vertical height in which to hang the array, again, our building could
> not accomodate such a system.
>
> As great as they are, unless your building is acousically large, it does
> not make much sense to use a line array. Alternatively, line arrays are
> excellent for outdoor events.


I think something is wrong here as there are many people who use line
arrays in their home.

http://www.audiodiycentral.com/resource/pdf/nflawp.pdf
http://diyaudio.com/forums/showthr [...] highlight=

http://66.216.98.167/mcprod/product_docs/XRT30br.pdf

>
> Here in the UK, I went to a "son et lumiere" style evening at Audley End
> House last summer, where there was a symphony orchestra and fireworks.
> There must have been 15,000 people there that evening and on either side
> of the stage was a line array column. The sound from quality was
> fantastic, with very little SPL variation over the entire audience depth
> (about 500m).
>
> Take a look at http://www.l-acoustics.com/pdfproda/wavefront.zip for
> more details on the theory behind line arrays.
>
> Chris W
>



--
Nothing beats the bandwidth of a station wagon filled with DLT tapes.

Archived from groups: rec.audio.tech (More info?)

Rich Andrews. wrote:

> A Bessel array is usually a horizontal array.

Strange that one of the two forms of Bessel array that work well is 5 x 5.

The other Bessel array that works well, 5 in a row, has the same
directional characteristics no matter which way it's roated.

Effective Performance of Bessel Arrays 2366218 bytes (CD aes5)
Author(s): Keele, Jr., D. B.
Publication: Volume 38 Number 10 pp. 723·748; October 1990
Abstract: The Bessel array is a configuration of five, seven, or nine
identical loudspeakers in an equal-spaced line array that provides the same
overall polar pattern as a single loudspeaker of the array. The results of a
computer simulation are described, which uses point sources to determine the
effective operating frequency range, working distance, efficiency, power
handling, maximum acoustic output, efficiency·bandwidth product, and
power·bandwidth product of the array. The various Bessel configurations are
compared to one-, two-, and five-source equal-spaced equal-level
equal-polarity line arrays. As compared to a single source, a five source
Bessel array is 14% (0.6dB) more efficient, can handle 3.5 (+5.4dB) more
power, and has 4 times (+6dB) the maximum midband acoustic output power, and
is usable for omnidirectional radiation up to the frequency where the
overall length is 11 wavelengths long. As compared to a two-source
equal-level in-phase array, a five-source Bessel array is 43% (2.4dB) less
efficient, can handle 1.75 (+2.4dB) more power, has the same maximum midband
acoustic output power, and is usable for omnidirectional radiation 10 times
higher in frequency. A working distance of 20 times the length of the Bessel
array was assumed, with the length of the Bessel array (center-to-center
distance of outside sources) being four times that of the two-source array.
Analysis reveals that the three Bessel arrays have equal maximum acoustic
output, but that the five-element Bessel array has the highest efficiency
and power·bandwidth product. The seven- and nine-source Bessel arrays are
found to be effectively unusable, as compared to the five-source array, due
to much lower efficiency, requirement for more sources, and poor
high-frequency performance. Judging polar peak-to-peak ripple and
high-frequency response, the performance of the Bessel array is found to
improve in direct proportion to the working distance away from the array.
Unfortunately the phase versus direction and phase versus frequency
characteristics of the Bessel array are very nonlinear and make it difficult
to use with other sources.

Archived from groups: rec.audio.tech (More info?)

I use baby line arrays in clubs and small ballrooms with great success. The
optimal minimum distance is less than 5 meters.

http://www.slsloudspeakers.com/LS8 [...] 0Array.htm

http://www.padrick.net/LiveSound/SLS/LS8695.htm

http://www.ribbonloudspeakers.com/_wsn/page2.html


"Chris Whealy" <chris.whealy.NO@SPAMsap.com> wrote in message
news:c5j0o9$7bs$1@news1.wdf.sap-ag.de...
> Rich Andrews. wrote:
> > I have been looking at various speaker designs and wondered why more
people
> > don't build or produce vertical arrays. Is it the cost involved or the
size
> > or ??? They certainly seem to have a number of good characteristics.
Am I
> > missing something?
>
> The church I go to recently looked into getting a vertical line array
> system, but it rapidly became apparent that our auditorium was too small
> for such a speaker system. In order to be in the far field, the
> audience should not be closer that 25 to 30 metres from the line array.
> Our audience is only 15m away. Also, you need a fairly large
> vertical height in which to hang the array, again, our building could
> not accomodate such a system.
>
> As great as they are, unless your building is acousically large, it does
> not make much sense to use a line array. Alternatively, line arrays are
> excellent for outdoor events.
>
> Here in the UK, I went to a "son et lumiere" style evening at Audley End
> House last summer, where there was a symphony orchestra and fireworks.
> There must have been 15,000 people there that evening and on either side
> of the stage was a line array column. The sound from quality was
> fantastic, with very little SPL variation over the entire audience depth
> (about 500m).
>
> Take a look at http://www.l-acoustics.com/pdfproda/wavefront.zip for
> more details on the theory behind line arrays.
>
> Chris W
>
> --
> The voice of ignorance speaks loud and long,
> but the words of the wise are quiet and few.
> --
>

Archived from groups: rec.audio.tech (More info?)

Chris Whealy wrote:

> The church I go to recently looked into getting a vertical line array
> system, but it rapidly became apparent that our auditorium was too
> small for such a speaker system.

That would be an economic choice, not a technical choice. Line arrays can be
made to work well in smaller rooms, but of course the line array would then
itself be smaller.

>In order to be in the far field, the
> audience should not be closer that 25 to 30 metres from the line
> array.

Actually, there are problems with being too close to a line array of a given
size, but the problem can be solved by using a smaller array.

> Our audience is only 15m away. Also, you need a fairly
> large vertical height in which to hang the array, again, our building
> could not accomodate such a system.

Again, the geometry of line arrays is scalable.

> As great as they are, unless your building is acousically large, it
> does not make much sense to use a line array. Alternatively, line
> arrays are excellent for outdoor events.

I've seen line arrays used to great advantage indoors. I've sat reasonably
close to them when they were operating and they remained highly effective.

There are useful things that can be done with arrays and AFAIK only with
arrays - these people were early pioneers:

http://www.duran-audio.com/Products/Intellivox.htm

> Here in the UK, I went to a "son et lumiere" style evening at Audley
> End House last summer, where there was a symphony orchestra and
> fireworks. There must have been 15,000 people there that evening and
> on either side of the stage was a line array column. The sound from
> quality was fantastic, with very little SPL variation over the entire
> audience depth (about 500m).

Arrays can provide similar benefits in smaller spaces.

> Take a look at http://www.l-acoustics.com/pdfproda/wavefront.zip for
> more details on the theory behind line arrays.

Other sources:

http://www.meyersound.com/support/papers/steering/

http://www.eaw.com/products/DSA/

http://www.audiosystems.ch/live/jb [...] glisch.pdf

Archived from groups: rec.audio.tech (More info?)

Chris Whealy wrote:

>> Example, not endorsement: see http://www.slsloudspeakers.com

> One of our prerequisites is that whatever speakers we buy,
> we need to have a trial run first to actually here what they
> are like in our environment. Some companies have been
> willing to accommodate this, others have not...

Don't ask me what SLS will do, ask them, or ask George Gleason. From
specs and from assuming that the are a local supplier so that you do not
have to worry about importing to test they seem to be a good idea. I am
glad that you got the points about having been somewhat mislead by some
of the sales people you have encountered.

> Also the 90deg conical directivity of the 112XT's

Not optimum for long throw ... not at all optimum. Wide horisontal is
OK, but the vertical pattern must be narrow to get sound projected and
to lift it over the heads of those closest to the array. Veree simply
late night explained.

> Chris W


Kind regards

Peter Larsen


--
*******************************************
* My site is at: http://www.muyiovatki.dk *
*******************************************

Archived from groups: rec.audio.tech (More info?)

François Yves Le Gal <flegal@aingeal.com> wrote in
news:6f0q70h65urf2mpekc5jsmn043a0mv0e6h@4ax.com:

> On Wed, 14 Apr 2004 04:47:48 -0000, "Rich Andrews." <nway@yihoo.com> wrote:

>
>>They certainly seem to have a number of good characteristics.
>
> And a number of poor ones.
>
>
>

Francois,

Would you elaborate on your last statement?

r


--
Nothing beats the bandwidth of a station wagon filled with DLT tapes.

Archived from groups: rec.audio.tech (More info?)

On Fri, 16 Apr 2004 13:37:48 -0000, "Rich Andrews." <nway@yihoo.com> wrote:

>Would you elaborate on your last statement?

Bessel arrays are sub-optimal when it comes to efficiency, and, at a more
general level, most types of vertical arrays show too broad a directivity
pattern for home appplications.

D.B. Keele wrote a very nice paper on this subject: "Effective Performance
of Bessel Arrays", JAES 38/10, 1990.

Archived from groups: rec.audio.tech (More info?)

On Fri, 16 Apr 2004 23:18:48 -0000, "Rich Andrews." <nway@yihoo.com> wrote:

>As a general rule, Bessell arrays are not vertical arrays.

They are usally of the x5 vertical type in domestic applications.

Archived from groups: rec.audio.tech (More info?)

Rich Andrews. wrote:
> François Yves Le Gal <flegal@aingeal.com> wrote in
> news:vdqv70pa4ovcism6l2jd6lobe4nvp8oogk@4ax.com:

>> D.B. Keele wrote a very nice paper on this subject: "Effective
>> Performance of Bessel Arrays", JAES 38/10, 1990.

Agreed. It's probably the definitive paper in the area of Bessel arrays.

> As a general rule, Bessell arrays are not vertical arrays.

As a rule it doesn't matter what the orientation of a 5-speaker bessel array
is.

The 5-speaker Bessel array has highly similar directivity in either
orientation. That is its major strength. This comes through very strongly if
you read the Keele article. It also is quite apparent if you listen to one.

> If one is looking for the miniature orchestra effect, then a line
> array is not for you.

This comment specifically does not apply to the 5-speaker Bessel array
because it is a line array that does not perform like many other line
arrays.

> If you are looking for the sense of a live
> performance with all the height, width, and depth, then a I think a
> line source is worth a listen.

Because of the Bessel array and some other configurations I've mentioned,
this generality is not very well-supported.

Archived from groups: rec.audio.tech (More info?)

On Sat, 17 Apr 2004 02:00:55 -0000, "Rich Andrews." <nway@yihoo.com> wrote:

>I akways thought they were horizontal like the one here:
>
>http://66.216.98.167/mcprod/product_docs/LS360om.pdf

The LS360 is a fairly standard multiway tower loudspeaker with an array of
tweeters.

>or the one here:
>http://66.216.98.167/mcprod/product_docs/CS350om.pdf

The CS350 is a conventional center speaker for HT applications, using the
same type of tweeter array, no wonder it is designed for horizontal
placement...

Archived from groups: rec.audio.tech (More info?)

On Sat, 17 Apr 2004 17:09:22 -0000, "Rich Andrews." <nway@yihoo.com> wrote:

>"The LS360 utilizes five tweeters wired to produce a Bessel Function
>Array."

And your point is? Fact is that the LS360 is a pretty standard multiway
loudspeaker which does happen to use a tweeter array, as anyone can verify:
http://66.216.98.167/mcprod/produc [...] duct_id=29

Now, let me kindly rephrase, just in case your neuron is stuck in neutral
mode, again: THE LS360 IS NOT AN ARRAY LOUDSPEAKER.

Back to normal programming. News at eleven.
FU2.

Archived from groups: rec.audio.tech (More info?)

On Sat, 17 Apr 2004 21:46:30 -0000, "Rich Andrews." <nway@yihoo.com> wrote:

>Your insults are noted and uncalled for.

There are no insults whatsoever in my post.
Your neuron must really be jammed.

>I leave you to you own opinions which are obviously not based on facts.

I've demonstrated that the McIntosh speaker wasn't a Bessel array, but only
used an array for it's tweeter section, and supplied a link so that anyone
could verify that fact.

>I also found it quite revealing that you attempted to thwart any response
>by setting the header "Followup-To" to junk.

The Follow-up to was duly signaled by FU2 at the end of my post.

Any other questions?

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"TonyP" <TonyP@optus.net.com.au> wrote in news:40836797$0$6018$afc38c87
@news.optusnet.com.au:

>
> "François Yves Le Gal" <flegal@aingeal.com> wrote in message
> news:1t9380dinbmcbm15e7rjkdbtn0puo376jf@4ax.com...
>> On Sat, 17 Apr 2004 21:46:30 -0000, "Rich Andrews." <nway@yihoo.com>
> wrote:
>>
>> >Your insults are noted and uncalled for.
>
>> There are no insults whatsoever in my post.
>> Your neuron must really be jammed.
>> The Follow-up to was duly signaled by FU2 at the end of my post.
>
>> Any other questions?
>
> Yes, If there were no insults, can you tell us what FU2 stands for ?
>
> TonyP.
>
>

I can guess why the "Followup-To" header was changed.

r


--
Nothing beats the bandwidth of a station wagon filled with DLT tapes.